Subwavelength imaging using a solid‑immersion diffractive optical processor  

作　　者：Jingtian Hu Kun Liao Niyazi Ulas Dinc Carlo Gigli Bijie Bai Tianyi Gan Xurong Li Hanlong Chen Xilin Yang Yuhang Li Cağatay Işıl Md Sadman Sakib Rahman Jingxi Li Xiaoyong Hu Mona Jarrahi Demetri Psaltis Aydogan Ozcan 

机构地区：[1]Electrical and Computer Engineering Department,University of California,Los Angeles,CA 90095,USA [2]Bioengineering Department,University of California,Los Angeles,CA 90095,USA [3]California NanoSystems Institute(CNSI),University of California,Los Angeles,CA 90095,USA [4]Department of Physics,Peking University,Beijing 100871,China [5]School of Engineering,Ecole Polytechnique Federale de Lausanne(EPFL),Lausanne,Switzerland [6]David Geffen School of Medicine,University of California,Los Angeles,CA 90095,USA

出　　处：《eLight》2024年第1期203-222,共20页e光学(英文)

基　　金：The Ozcan Research Group at UCLA acknowledges the support of Fujikura Inc.The Jarrahi Group at UCLA acknowledges the support of the Harvey Engineering Research Prize from the Institution of Engineering and Technology.

摘　　要：Phase imaging is widely used in biomedical imaging,sensing,and material characterization,among other fields.However,direct imaging of phase objects with subwavelength resolution remains a challenge.Here,we demonstrate subwavelength imaging of phase and amplitude objects based on all-optical diffractive encoding and decoding.To resolve subwavelength features of an object,the diffractive imager uses a thin,high-index solid-immersion layer to transmit high-frequency information of the object to a spatially-optimized diffractive encoder,which converts/encodes high-frequency information of the input into low-frequency spatial modes for transmission through air.The subsequent diffractive decoder layers(in air)are jointly designed with the encoder using deep-learning-based optimization,and communicate with the encoder layer to create magnified images of input objects at its output,revealing subwavelength features that would otherwise be washed away due to diffraction limit.We demonstrate that this all-optical collaboration between a diffractive solid-immersion encoder and the following decoder layers in air can resolve subwavelength phase and amplitude features of input objects in a highly compact design.To experimentally demonstrate its proof-of-concept,we used terahertz radiation and developed a fabrication method for creating monolithic multi-layer diffractive processors.Through these monolithically fabricated diffractive encoder-decoder pairs,we demonstrated phase-to-intensity(P→I)transformations and all-optically reconstructed subwavelength phase features of input objects(with linewidths of~λ/3.4,whereλis the illumination wavelength)by directly transforming them into magnified intensity features at the output.This solid-immersion-based diffractive imager,with its compact and cost-effective design,can find wide-ranging applications in bioimaging,endoscopy,sensing and materials characterization.

关 键 词：Diffractive processors Solid immersion imaging Phase-to-intensity transformations 

分 类 号：O43[机械工程—光学工程]